Description

Generates all of the scores of the Functional Assessment of Cancer Therapy -
Nasopharyngeal Cancer (FACT-NP, v4) from item responses.

Usage

1

Arguments

df

A data frame with the FACT-NP items, appropriately-named.

updateItems

Logical, if TRUE any original item that is
reverse coded for scoring will be replaced by its reverse coded version
in the returned data frame, and any values of 8 or 9 will be replaced
with NA. The default, FALSE, returns the original items
unmodified.

keepNvalid

Logical, if TRUE the function
returns an additional variable for each of the returned scale scores
containing the number of valid, non-missing responses from each
respondent to the items on the given scale. If FALSE (the
default), these variables are omitted from the returned data frame.

Details

Given a data frame that includes all of the FACT-NP (Version 4) items as
variables, appropriately named, this function generates all of the FACT-NP
scale scores. It is crucial that the item variables in the supplied data
frame are named according to FACT conventions. For example, the first
physical well-being item should be named GP1, the second GP2, and so on.
Please refer to the materials provided by http://www.facit.org for the
particular questionnaire you are using. In particular, refer to the left
margin of the official questionnaire (i.e., from facit.org) for the
appropriate item variable names.

Value

The original data frame is returned (optionally with modified
items if updateItems = TRUE) with new variables corresponding to
the scored scales. If keepNvalid = TRUE, for each scored scale an
additional variable is returned that contains the number of valid
responses each respondent made to the items making up the given scale.
These optional variables have names of the format SCALENAME_N.
The following scale scores are returned:

PWB

Physical Well-Being subscale

SWB

Social/Family Well-Being subscale

EWB

Emotional Well-Being subscale

FWB

Physical Well-Being subscale

FACTG

FACT-G Total Score (i.e., PWB+SWB+EWB+FWB)

NPS

Nasopharyngeal Cancer subscale

FACT_NP_TOTAL

FACT-NP Total Score (i.e., PWB+SWB+EWB+FWB+NPS)

FACT_NP_TOI

FACT-NP Trial Outcome Index (e.g., PWB+FWB+NPS)

Note

Keep in mind that this function (and R in general) is case-sensitive.

All variables should be in numeric or integer format.

This scoring function expects missing item responses to be coded as NA,
8, or 9, and valid item responses to be coded as 0, 1, 2, 3, or 4. Any
other value for any of the items will result in an error message and no
scores.

Some item variables are reverse coded for the purpose of generating the
scale scores. The official (e.g., from http://www.facit.org) SAS
and SPSS scoring algorithms for this questionnaire automatically replace
the original items with their reverse-coded versions. This can be
confusing if you accidentally run the algorithm more than once on your
data. As its default, scoreFACT_NP DOES NOT replace any of your
original item variables with the reverse coded versions. However, for
consistentcy with the behavior of the other versions on
http://www.facit.org, the updateItems argument is
provided. If set to TRUE, any item that is supposed to be
reverse coded will be replaced with its reversed version in the data
frame returned by scoreFACT_NP.